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Seiko’s current Rotocall SMGG21 is a fashion-forward reinterpretation of the 1982 digital watch enthusiasts nicknamed the “Astronaut.” It keeps the original’s defining octagonal rotary switch—rotate the bezel to change modes—while updating the case and color treatment in stainless steel. A related reissue, the SMGG19, uses the same core A824 platform, so the practical choice is primarily about styling, market availability and wrist presence.
What is the Seiko Astronaut watch called?
The watch is Seiko’s Rotocall. The original digital design debuted in 1982 and became known informally as the “Astronaut” because of its association with astronauts and spaceflight. Seiko’s present-day SMGG21 product description identifies the model as being based on that 1982 Rotocall design and highlights its octagonal rotary switch.
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That control is the watch’s signature idea. Instead of selecting every function with conventional pushers, the wearer rotates the bezel to move between modes. The reissue preserves that interaction alongside a multi-function digital display, making it recognizably Rotocall rather than merely a square retro watch.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsIs the Seiko Rotocall a real NASA watch?
It has a genuine astronaut-wearer history, but it should not be described as an official NASA-issued watch. Wallpaper* reported that the original was never officially issued by NASA while associating it with use on more than 160 space missions and with astronauts including Sally Ride and Kathryn Sullivan. That makes the “Astronaut” label a story of real-world use and enthusiast culture, not evidence of a NASA procurement program.
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- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
What changed on the new Rotocall?
The operating concept and broad function set remain rooted in 1982. The makeover is mainly visual and material: the current watch presents the retro module in a contemporary stainless-steel case with refreshed colorways. “Stylish” is a design judgment rather than a measurable specification, but the result is less like a fragile period novelty and more like a deliberately styled everyday watch.
SMGG21 specifications
| Specification | SMGG21 |
|---|---|
| Movement | Seiko A824 quartz |
| Accuracy | ±20 seconds per month |
| Battery life | Approximately three years |
| Case material | Stainless steel |
| Diameter | 37.0 mm |
| Thickness | 10.6 mm |
| Lug-to-lug | 43.5 mm |
| Crystal | Hardlex |
| Water resistance | 10 bar |
| Listed weight | 107 g |
Functions
- Rotary bezel switch for changing modes
- Chronograph measuring up to 99:59:59; hundredths-second increments change to one-second increments after 60 minutes
- Timer counting down from up to 100 minutes
- Single alarm
- Dual time
- Full automatic calendar through 31 December 2074
- Battery warning and LED internal illumination
The A824 instruction manual specifies the stopwatch’s 99-hour, 59-minute and 59-second maximum. The hundredths display is therefore intended for shorter events; after one hour, the resolution becomes whole seconds.
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SMGG19 vs. SMGG21: which Rotocall should you buy?
Both current references document the same basic 37 mm case scale, 10.6 mm thickness and A824-style multi-function architecture. Neither is a fundamentally different movement or complication package. Choose between them by appearance and what you can actually buy in your region.
| Decision point | SMGG19 | SMGG21 |
|---|---|---|
| Design | Alternative Rotocall colorway and finishing | Alternative colorway with its own contemporary styling |
| Core platform | Same Rotocall concept and A824 architecture documented for the reissues | A824 quartz; rotary switch and multi-function digital display |
| Wrist fit | 37 mm class; compact 43.5 mm lug-to-lug proportions are the useful reference | 37.0 mm diameter, 10.6 mm thick, 43.5 mm lug-to-lug |
| Price and availability | Vary by country, seller and stock | Vary by country, seller and stock |
On a smaller or medium wrist, the 37 mm diameter and 43.5 mm lug-to-lug measurement should wear compactly, while the 107 g listed weight gives the steel case more presence than a lightweight resin digital watch. Buyers who care most about the unusual rotary control and the unusually broad timer, alarm, calendar and chronograph package will get essentially the same functional proposition from either reference; the colorway and local availability should decide the purchase.
Rank #3
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- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
What to check before buying
- Confirm the exact reference on the listing: SMGG19 or SMGG21.
- Check that the seller is authorized or otherwise provides a credible authenticity and warranty path.
- Verify current regional pricing and stock immediately before ordering, since both can change.
- Measure your wrist against the 43.5 mm lug-to-lug length, not just the 37 mm diameter.
- Remember that 10 bar water resistance is a rating for the watch, not a guarantee against damage from every activity; follow Seiko’s operating and water-use guidance.
Why the Rotocall still matters
Most retro digital reissues reproduce a case and display. The Rotocall also reproduces a method of interaction. Rotating the bezel to select modes gives the SMGG21 a mechanical gesture that distinguishes it from ordinary button-operated digitals, while the stainless-steel proportions make the 1982 idea easier to wear with modern clothing. Its space connection is best understood as documented wearer history rather than an official NASA credential, and its appeal rests on that combination of provenance, unusual control design and practical everyday functions.
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Rank #4
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- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
